Objective comparison of particle tracking methods

Particle tracking is of key importance for quantitative analysis of intracellular dynamic processes from time-lapse microscopy image data. Because manually detecting and following large numbers of individual particles is not feasible, automated computational methods have been developed for these tasks by many groups. Aiming to perform an objective comparison of methods, we gathered the community and organized an open competition in which participating teams applied their own methods independently to a commonly defined data set including diverse scenarios. Performance was assessed using commonly defined measures. Although no single method performed best across all scenarios, the results revealed clear differences between the various approaches, leading to notable practical conclusions for users and developers

Icy: an open bioimage informatics platform for extended reproducible research

International audienceCurrent research in biology uses evermore complex computational and imaging tools. Here we describe Icy, a collaborative bioimage informatics platform that combines a community website for contributing and sharing tools and material, and software with a high-end visual programming framework for seamless development of sophisticated imaging workflows. Icy extends the reproducible research principles, by encouraging and facilitating the reusability, modularity, standardization and management of algorithms and protocols. Icy is free, open-source and available at http://icy.bioimageanalysis.org/

Prions hijack tunnelling nanotubes for intercellular spread.

International audienceIn variant Creutzfeldt-Jakob disease, prions (PrP(Sc)) enter the body with contaminated foodstuffs and can spread from the intestinal entry site to the central nervous system (CNS) by intercellular transfer from the lymphoid system to the peripheral nervous system (PNS). Although several means and different cell types have been proposed to have a role, the mechanism of cell-to-cell spreading remains elusive. Tunnelling nanotubes (TNTs) have been identified between cells, both in vitro and in vivo, and may represent a conserved means of cell-to-cell communication. Here we show that TNTs allow transfer of exogenous and endogenous PrP(Sc) between infected and naive neuronal CAD cells. Significantly, transfer of endogenous PrP(Sc) aggregates was detected exclusively when cells chronically infected with the 139A mouse prion strain were connected to mouse CAD cells by means of TNTs, identifying TNTs as an efficient route for PrP(Sc) spreading in neuronal cells. In addition, we detected the transfer of labelled PrP(Sc) from bone marrow-derived dendritic cells to primary neurons connected through TNTs. Because dendritic cells can interact with peripheral neurons in lymphoid organs, TNT-mediated intercellular transfer would allow neurons to transport prions retrogradely to the CNS. We therefore propose that TNTs are involved in the spreading of PrP(Sc) within neurons in the CNS and from the peripheral site of entry to the PNS by neuroimmune interactions with dendritic cells

Objective comparison of particle tracking methods

International audienceParticle tracking is of key importance for quantitative analysis of intracellular dynamic processes from time-lapse microscopy data. As detecting and following large numbers of individual particles by hand is not feasible, state-of-the-art computational methods for these tasks have been developed by many groups worldwide. Aspiring an objective comparison of methods, we gathered the community and organized, for the first time, an open competition, in which participating teams applied their own methods independently to a commonly defined data set including diverse scenarios, and performance was assessed using commonly defined measures. While no single method performed best across all scenarios, the results revealed clear differences between the various approaches, leading to important practical conclusions for users and developers